Rice straw cellulose microfiber reinforcing PVA composite film of ultraviolet blocking through pre-cross-linking

Rice straw cellulose microfiber (CMF) was obtained through the gentle low-temperature phase transition method. Then, NaIO₄ was utilized to modify CMF by selective oxidation to prepare aldehyde CMF (a-CMF) to improve the reactivity of the CMF. Finally, the a-CMF reinforced polyvinyl alcohol (PVA) composite films were prepared through a pre-cross-linking and solvent casting approach. The cross-linking network formed by a-CMF and PVA through the aldolization reaction significantly improved the mechanical properties of the a-CMF/PVA composite film. The tensile strength of a-CMF-2/PVA was 37.54 ± 0.77 MPa, which was higher than 25.88 ± 2.97 MPa of the pure PVA. SEM results showed that the fracture surface of the a-CMF/PVA composite film with the cross-linking network was smooth. In addition, prepared a-CMF-2/PVA composite films had a transmittance of over 80 % in the visible light range, and also possessed excellent UV blocking property.